(a). Field of the Invention
The present invention is related to a plant monitoring/controlling apparatus for monitoring/controlling a subject plant, for instance, a thermal power plant or a nuclear power plant, in particular, a system in which a plurality of terminal units are arranged via a network.
(b). Description of the Related Art
Conventionally, in order to improve reliability of a plant monitoring/controlling apparatus with employment of a powerful computer capable of managing programs and data in a batch mode, a distributed type system has been proposed in which the overall function of this plant monitoring/controlling apparatus is subdivided into several sub-divided functions. Then, each of these sub-divided functions is executed by a plurality of small-scaled computers, and, thus, all of the required functions can be realized. JP-A-7-230430 laid open in 1995 describes such a conventional system in which, when the information is transmitted/received among these computers distributed in this system, the information can be transmitted without paying any attention to the operation conditions of the counter party.
However, the above-described related art clearly describes the transmission/reception of the information, but never discloses synchronizations of information among computers capable of processing such information which should be synchronized.
In plant monitoring/controlling apparatus employing distributed type systems, information which is required to be synchronized must be shared among a plurality of terminal units.